Ultra Simple PHP Profiler

profile.php

<?php
  $_start = 0;
  $_subdata = '';

  function profile_start() {
    global $profile;
    if ( $profile ) {
      global $_start, $_subdata;
      $_start = microtime(true);
      $_subdata = '';
    }
  }

  function profile_end( $data ) {
    global $profile, $_subdata;
    if ( $profile ) {
      global $_start;
      // open file
      $fd = fopen("/tmp/profile.csv", "a");
      // write string
      fwrite($fd, ( microtime(true) - $_start ) . "," . $data . "\n");
      fwrite($fd, $_subdata );
      // close file
      fclose($fd);
    }
  }

  function profile_info( $q ) {
    global $profile, $_subdata, $_start;
    if ( $profile ) {
      $_subdata .= (microtime(true) - $_start) . ",\"- " . $q . "\"\n";
    }
  }

  function mysql_queryx( $q ) {
    global $profile, $_subdata;
    if ( $profile ) {
      $pre = microtime(true);
      $result = mysql_query( $q );
      $_subdata .= (microtime(true) - $pre) . ",\"- " . $q . "\"\n";
      return $result;
    }
    else {
      return mysql_query( $q );
    }
  }
?>

profiler_usage.php

<?php
$profile = true;
require_once "profile.php";
profile_start();
// ...
$query = mysql_queryx( "select status from table" );
// ...
profile_info( "checkpoint" );
// ...
profile_end( "page" );
?>